(a) Field of the Invention
The present invention relates to an exhaust gas recirculation system of a vehicle. More particularly, the present invention relates to an exhaust gas recirculation system of a vehicle with a recirculation gas pathway in a cylinder block, configured such that coolant in the water jacket cools the recirculated exhaust gas, and supply of the recirculated exhaust gas is controlled based on driving conditions by a recirculation valve.
(b) Description of the Related Art
Generally, the amount of NOx in exhaust gas is high in an oxygen rich air mixture. A typical the exhaust gas recirculation system reduces the amount of NOx in the exhaust gas by recirculating a portion of the exhaust gas to the air mixture, thus reducing the oxygen ratio in the air mixture.
A hot EGR system retards ignition and reduces the air/fuel ratio, and a cooled EGR system lowers the temperatures of the combustion chamber and hinders combustion by cooling the recirculated exhaust gas. The hot and cold exhaust gas recirculation systems can be used together, such as by using the hot exhaust gas recirculation system under low load and the cold exhaust gas recirculation system under medium and high loads.
The cold exhaust gas recirculation system includes a cooler that cools the recirculated exhaust gas. However, the cooler is large and heavy. In addition, an exhaust gas recirculation valve may not control the amount of recirculated exhaust gas in accordance with driving conditions.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.